Electric crane.



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LE. HOLLAND. ELECTRIC CRANE.

\ APPLIATION FILED NOV/19, 1901.

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J. E. HOLLAND.

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ELEGTRIG ORANB.

APPLICATION FILED NOV. 19, 1901.

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ELECTRIC CRANE.

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No. 717,994. h PATENTED JAN. 6, 1903.

J. H. HOLLAND.

ELECTRIC CRANE.

APPLICATION FILEDNOV. 19, 1901.

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. J. H. HOLLAND.

ELECTRIC CRANE.

APPLIOATIDN II)LBD NOV. 19, 1901.

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STATES llivrrn ATENT OFFICE.

JOHN H. HOLLAND, OF COLUMBUS, OHIO, ASSIGNOR TO CASE MANUFAC- TURINGCOMPANY, OF COLUMBUS, OHIO, A CORPORATION OF OHIO.

ELECTRIC CRANE.

SPECIFICATION forming part ofl Letters Patent No. 717,994, dated January6, 1903.

Application led November 19, 1901. Serial No. 821888. (No model.)

T0 LZ whom, it muy concern:

Beit known thatI, JOHN H. HOLLAND,a citizen of the United States, and aresident of Columbus, in the county of Franklin and State of Ohio,haveinvented certain new and useful Improvements in Electric TravelingCranes, of which the following is a specification.

My invention though adapted for general use is designed more especiallyfor the difficult purpose of handling hot or cold ingots, in chargingheating-pits, or taking ingots out of pits and placing them onroll-tables or in chairs ready for the rolls.

The object of the invention is to provide a crane employingchainscapableofperforining all required movements of Whatever naturesuch astraversing the bridge lengthwise of the building, traversing the trolleylengthwise of the bridge, hoisting and lowering the load, opening andclosing the tongs, and tu rning or rotating the tongs to meet any angleat which it may be required to deposit the ingot in the pits or upon therolltable-all these movements being reversible, the direction of eachbeing governed by the operator. These objects are fully attained bycertain novel principles and details otrconstruction and arrangementsand combinations of parts,

that are hereinafter fully described, and the novel features ot' whichare particularly pointed out in the claims, reference being had to theaccompanying drawings, forming part of this specification, in whichjFigure l is a side elevation of opposite ends of the bridge with theintervening portion broken away, showing the traversing wheels, theiractuating-motor, and the connections through which they are caused torevolve in` unison; also, a side elevation of the two-part trolley whichtraverses the bridge, with the motor for winding the drums and the motor`for rotating the upper portion of the trolley upon the lower. In thisfigure the upper portion of the trolley is rotated upon the lower ninetydegrees from the relative` position of these parts'in some of theremaining figures Fig. 2 is a plan of parts shown in Fig. 1, with theupper portion ofthe trolley removed and one of the two similar pairs ofbridge traversing wheels broken away. Fig. 3 is an elevation of thatside of the trolley upon which are mounted the ino tors for driving androtating it. Fig. 4 is a plan of the trolley, showing the motor forwinding the drums located in the center thereof and the motors forrotatingand traversingit located, respectively, above and beyond oneside thereof. Figs. 5 and 6 are elevations of the ends of the trolleycorresponding, respectively, to the bottom and top of Fig. 4 and to theleft and right hand ends of Fig. 3. Fig. 7 is a horizontal section ofthe upper portion of the trolley through the axes of the winding-drums,the plane of section and the direction of view being indicated by theline and arrows 7 7 in Fig. Fig. 8 is a vertical section through thetrolley, taken on the line S 8 and looking in the direction of thearrowsin Fig. 4. Fig. 9 is a vertical section through the trolley on thebroken line 9 9, Fig. 8, and looking in the direction of the arrows inFig. S. Fig. l0 is a perspective view ot the three Winding-drums andtheir gear, through which they are driven from a common motor. Fig. 11is a perspective view showing the three winding-drums and theirpyramidal construction of iiexible winding connection, through which theload is forced to turn in unison with and prevent ed from turningindependently of the rotating portion of the trolley or swinging in anydirection. Figs. 12, 13, and 14 are sectional views of the releasing andpick-up clutch, which permits lost motion between the intermediate andthe two end drums for opening and closing the tongs, Fig. 12 being asection taken vertically through the center of Figs. 13 and 14, Fig. 13a section on the line 13 13, Fig. 12, looking in the direction of thearrow, and Fig. 14 being a section on the line 14 14, Fig. 12, lookingin the direction of the arrow.

A represents the bridge, which isprovided with end trucks B,mounting-wheels C, that run on rails D and receive rotary motion from acommon bridge-motor E.

F represents the trolley, provided with wheels G, which run upon rails Hupon the bridge and are driven by a trolley-motor I, Fig. 3, also withan upper rotating part f, carrying a turning-motor J, drums K L M,fromwhich depends a system of six chains 7c Z m, and a drum-Windingmotor N.

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The traveling bridge may be of usual boxgirder construction with its endvtrucks secured accurately in parallelism upon the rails.

To traverse the brclgc.-In order to drive the wheels C at opposite endsof the bridge uniformly from the bridge-traversing motor E, and thusimpart equal traveling movement to both ends of the bridge and keep itat all times normal to the track on which it runs, motion is transmittedfrom motorshaft 1 through a pinion 2 to a gear-wheel 3, fixed on one endof a loose sleeve 4, thence through a pinion 5 to a gear-wheel 6, fixedon a short shaft 7, thence through pinion 8 on the other end of shaft 7to a gear-wheel 9, fixed on the counter-shaft 10, extending from end toend ot' the bridge, and finally through pinions 1l, fixed on oppositeends of the shaft 10, to gearwheels 12, fixed upon the short shafts 13,which carry the wheels to be driven. 14 represents fiange-couplings,which in addition to facilitating the assembling of the parts facili-Tate dividingr the shaft 10 and procuring a relative rotation betweenits parts at any time to aline the bridge perpendicularly to the track.

. Tracersz'ng the trolley-Any suitable connections may be employed fortransmitting rotation from the trolleymotor I to the wheels G. 'I haveshown the bevel-pinion 15 meshing with the bevel gear-wheel 16 on shaft17, which communicates rotation through`reducing-gear 18, 19, 20, and2l, the last-named gear-Wheel being fixed upon one of the trolley-axles22, on which are also fixed one pair of the wheels G. y

Rotating the trolley-To render the upper portion f of the trolleyreadily rotatable upon the base of the trolley, the formeris providedwith a circular series of grooved rollers 23, mounted on radial axes inpedestals 24 and tting a circular track 25 on the base F. A guard-liange26 receives the rollers 26L to prevent displacement of the rotatableportion of the trolley in the event of its derailment. Within theguard-flange 26 is acircular rack 27, Figs. 2, 4, 7, 8, 9, with whichmeshes a pinion 28 on the lower end of a vertical shaft 29, whichcarries at its upper end a worm-wheel 30, rotated by a Worm-screw 3l onthe shaft 32 of trolley-rotating motor J. worm-wheel cannot drive theworm, the turning of the trolley and rotation or angular movement of theioad may be controlled to the desired degree by simply regulating theduration of current-supply. There can be no racing of the parts.

H0t'st2'ng.-As previously stated, the hoisting is accomplished bywinding chains 7c m upon the drums K and M. These drums with theirchains can be best seen in Fig. 11. The drum L with its chains l do notsupport any important part of the load and merely serve to open andclose the tongs by moving their fulcrum-plates upward or downwardrelatively to the tongs members. Except for the relative rotationbetween the drum L and the Since the drums K and M the three drumsrotate in unison, the drums K and M for the purpose of raising orlowering the load and the drum L to wind up or unwind the chains whichserve to open and close the tongs. All of the drums are driven by thehoisting-motor N through connections which will now be described, therelative motion between the drum L and the drums K and M being caused bymeans to be hereinafterdescribed in connection with the description ofthe control of the tongs.

33 represents the winding motor shaft, which is connected by aliange-coupling 34 with a short shaft, upon which are fixed large andsmall gear-wheels 35 and 36, capable of being shifted in an axialdirection, so as to bring the larger wheel 35 into engagement with awheel 38 or the smaller wheel 36 into engagement with a wheel 39. Boththe wheels 38 and 39 are arranged to rotate in unison, the wheel 39being keyed upon a sleeve extending integrally from the wheel 38. If therotation of the motor-shaft 33 is imparted to the wheel 38 directlythrough the wheel 35, the wheel 38 receives a faster rotation than if itis driven indirectly through wheels 36 and 39. As the wheel 38 controlsthe rotation of the drums, means is thus provided for varying therapidity of the hoisting and lowering movements. These parts can bereadily seen in Fig. 9, in which the driving-motor is omitted from itsshaft 33. By referring to Fig. 10 it will be seen that the wheel 38meshes with two identical wheels 41 42, which are keyed to shafts 43 44,so that said shafts are rotated in the same direction-that is to say,with their adjacent faces moving in opposite directions. 1t will be seenin Fig. 7 that the shafts 43 44 project through but are not connectedwith the drums K and M, and they constitute the journals for said drums.The shafts carry on their opposite ends pinions 45 46, which, it will beseen upon reverting to Fig. 10, as also upon reference to Fig. 6, meshwith the relatively larger gear-wheels 47 48, keyed upon shafts 49 50,which extend across the trolley above the drums, Figs. 3 and 4. Atintermediate points on the shafts 49 50 are keyed pinions 51 52, whichmesh with gear-wheels 53 54 or toothed heads on the drums K and M. Thedrums are thus rotated by reduction-gear, which reduces the motion verygreatly. This gear is partly on one end and partly on the other end ofthe drums and the connection between the parts in each case is a shaftthat extends axially through the drum that is to be driven and uponwhich the drum finds its bearing. The parts being identical for eachdrums driving connections, it follows that the drums will receiveidentical motion from the common sourcethe winding-motor N. Theintermediate or tongs-controlling drum receives its driving motion fromone of the shafts 49 or 50. In the present case it is shown connectedwith the shaft 49 through IOO IIO

a pinion 55 on said shaft, that meshes with an idler or transmittingpinion 56, and through it drives a second idler 57, that reverses thedirection of rot-ation and meshes with the toothed head 58 on thecontrolling-drum L and rotates the latter in the same direction as thedrums K and M are rotated in and at the same rate of speed.

59 represents a pinion meshing with the gear-wheel 42 on the shaft 44and keyed to a short shaft 60, which carries a brake-wheel 6l, to whichis applied, as seen in Figs. 3, 4, and 5, a brake-band 62, connectedwith a controlling-lever 63, fulcrumed at 64 and carrying an armature 65of a solenoid 66. These parts are constructed in a manner well known,having been used for many years in electric elevators and likeapparatus. The solenoid 66 is either in shunt or direct electricalconnection with the source of supply for the electric winding-motor N,so that when the motor is driven the solenoid is energized and raisesits core to release the brake-band 62 and permit the parts to rotatefreely; but when the motor is cut out the weight.- of the core orarmature of the solenoid `applies the brake and arrests the hoisting orlowering motion at once.

Controlling the tonga-As already stated, the opening and closing of thetongs is controlled by changing the length of the opening-chains Z onthe drum L relatively to the hoisting-chains 7c mon the drums K M-thatis to say, if the opening-chains Z sustain the main weight of the tongsthe latter will open, While if the weight of the tongs is merelysustained by the hoisting-chains the grippingjaws will be drawn togetherand the tongs closed. This change in relative length ofthe chains mustbe accomplished by dilerentiating the rotation of the intermediate drumrelatively to the two outer drums. Since the dii-ums are driven from acommon source of power, this differentiating is best accomplished byretarding the winding connections of one set of the chains relatively tothewinding connections of the other, and for reasons of economy thisfeature is best embodied in the single intermediate drum. lf therotation of the intermediate drum be` retarded while all the chains arebeing wound up"`or as the winding motion commences, obviously theopening-chains will not be wound as fast as the others, and willtherefore be slackened and the hoisting-chains will have the effect offorcing the jaws together and gripping in the object over which they aresuspended in gripping relation. If the intermediate or opening chaindrum is retarded While the chains are being unwound, obviously theintermediate or opening chain will have shortened relatively to thehoisting-chains and will sustain the main load of the tongs while theouter hoisting-chains slacken and allow the up Wardly projectingcontrolling-levers of the tongs to fall apart and open the tongs. Bythis motion the previously-gripped obj ect will be released, or if rthetongs are empty they will be opened ready to grip an object. Othermotions-such as tilting ladles, operating clam-shell scoops, and suchlikemay be accom plished by these same changes in the rel-' ativelengths of the chains; but I will describe the means for accomplishingthese changes in connection with' tongs for handling steel ingots, itbeing understood that this assocation of these features of my inventionis for the purpose of illustration and not ofI limitation.

The construction which admits of the abovedescribed operation of thetongs will now be described.

Referring to Figs. 9 to 14, it will be seen that the drivinggear 58 ofthe intermediate drum L is mounted through a hub 67 upon the shaft 68 ofdrum L, with an interposed bush* ing 69, said wheel 58 being therebyadapted to turn relatively to the shaft 68, while the drum is fixed uponsaid shaft by a" key 70. (Figs. 9 and l2.) Driving connection betweenthe wheel 58 and the drum L in the `direction of winding is establishedthrough `teeth 7l on the drum and pawls 72 pressed into engagement withsaid teeth by spring 73 and pivotally mounted in bearings 74 on afriction-strap 75, which bears through a leather facing 76, confined byan annular rim 77 upon a sheave 78, formed integral with and otherwisefixed upon the drum L. Wheel 58,which it has already been seen ispositively driven at all times in unison with the hoisting-drums K andM, is thus brought into driving connection with drum L in the directionof winding through the friction-strap 76, which is in frictional drivingconnection with the sheave 78 on said drum. If the wheel 58 is rotatedin the direction of uuwinding the chains, it does not impart positiverotation to the drum, hut permits such rotation which results from theweight of the chains hanging from the drum and limits the rate of saidunwinding motion by the pawl-and-ratchet connection described. If sameinfluence, for example, by means hereinafter described is brought tobear upon the drum to retard this rotation in the direction ofunwinding, the ratchet connection permits the wheel 58 to continue, andthedifferentiation of rotation between the intermediate drum and theouter drums isthereby accomplished, with the consequent shortening o'fthe opening-chain and the opening of the tongs. If while the drum isbeing wound up some iniiuence is brought to bear to retard rotation ofthe drum L, no slip can take place in the pawl-and-ratchet connection;but this slip is provided for in the friction-strap connection 76, 77,and 78. To regulate the friction of strap 76, it is divided into twosemicircular parts, which are connected at one end by a pin 79 passingthrough ears 8O on the parts of the strap and carrying springs 8l, thatare confined between said ears and shoulders 82 on the boltin such amanner as to force the two ears 80 together, the op- IOC posite ends ofthe two parts of the frictionstrap being connected by a bolt 83 passingthrough ears 84 and having an adjustmentnut 85. The ears 84 are spacedapart a suitable distance to permit adjustment of the nut 85.-vBy'forcing the ears 84 together the ears 80 are'separated, the springs81 compressed, and the pressure of the strap upon the sheave 78 isincreased. Means is thus provided for regulating the friction betweenthe strap 76 and the sheave 78 to a nicety. The degree of slippingmotion of the wheel 58 and the drum L is limited by a radial stop 86,Fig. 14, on the hub 67, which engages the segmental lug 87 on the drumL. After a relative motion between the wheel 58 and the drum L(represented by the circumferential distance :ry in Fig. 14) has takenplace in either direction further movement of the wheel 58 is positivelyimparted to the drum L by engagement of stop 86 with lug 87, andthereafter the drum L is compelled to rotate in unison with the drums Kand M, while the diierence in length of the chains established by theslip motion is maintained until the direction of the motor is reversedand the slip motion in the contrary direction is permitted.

In order to bring a retarding iniiuence u pon the drum L, and thus causethe slip motion referred to, I provide an electromagnetic brake thatoperates upon the wheel 88, Fig. l0,which is positively keyed by aspline 89 to the shaft 68, to which the drum L is keyed, Fig. 9. Thiselectromagnetic brake comprises a brakeband 90, Figs. 4, 8, and 9,having its opposite end connected eccentrically to the torsionshaft 91,which carries the lever 92, Fig. 6, from one end of which is suspended aWeight 93, that turns the shaft 91 in a direction to clamp thebrake-band 90 upon the Wheel 88, and from the other end the core orarmature 94 of a solenoid 95, which may be energized at will to rock theshaft 91 in opposition to the weight 93 and relieve the frictionalcontact of the brake-band 88. lVhen the weight 93 is acting, thebrake-band imposes such a load upon the drum L that it will cause theslipping or lost motion in said drum already referred to; but if thesolenoid 95 is energized so as to rock the lever 92 in opposition to theWeight 93 the brake-band 88 will be released and the drum L will berotated without lost motion.

Then the drums are rotating in the direction of winding up the chains,it has been seen that the pawl-and-ratchet connection between the wheel58 and drum L cannot slide, but is positively engaged. The sliding whichtakes place in this direction must be inthe friction device 76 77 78.The frictional contact at this point is just sufficient with a safemargin to perform the Work of Winding up the opening chain. If theretarding-brake 88 90 adds its retarding influence to the work which isbeing performed in winding up the chain, the load imposed upon the drumWill be sufficient to cause slipping of the friction device 76 78.

In unwinding the Weight-load of depending chain on the drum L isassisting the rotation, and if the frictional driving connection 76 78were employed it would be impracticable to retard the drum with the samebrake that retards its rotation in winding up when rotation is imposedby the weight of the chain. For this reason the paWl-and-ratchetconnection 72 73 is provided, and with this in use the retarding-brakesimply has to brake the tendency of the drum to rotate under the weightof the chain, while the wheel 58 will continue in advance of the drum.

Pyramidal chain s t/Szfcm.-The iinal feature of my invention isrepresented in Figs. 7, 8, 9, and 11, from which it will be seen thatthe six chains form au inverted pyramid, the base ot' which isrepresented by a b c d and the apex by c in Figs. 7 and 11. With thisarrangement of chains it is impossible for the load to materially twistor swing, and it consequently remains vertically beneath the trolley,partakes of all the trolleys horizontal movements, and rotates with thetrolley accurately. Thus it is possible to place an ingot accuratelyeither in the heating-pit, where it is necessary to have the side of aningot rest fiat against the side of the pit, or to place ingots indifferent corners of the pit, so that they will not touch one another;also to convey the ingot to the chair at the rolling-table and place itaccurately therein and to execute any movements with rapidity andprecision. This is a most important novel result, since it hasheretofore been impracticable to do this with cranes employing singlehoisting-chains, or a system of chains arranged in one plane, withoutthe assistance of several attendants using prods to prevent swinging andtwisting of the ingot. Owing to diiiculties heretofore experienced withchain cranes, they had prior to my invention been largely superseded bythe use of the expensive plunger type of cranes, in Which the supportfor raising and lowering the load and rotating it is a vertical pistonor rack-bar which requires a superstructure or derrick above the trolleyand an expensive inclosure affording large head-room.

The chains 11, depending from the intermediate drum and connecting withthe fulcrum-blocks of the tongs, afford additional stability to thepyramidal suspended system, and these results obtain notwithstandingchanges in the relative length of the chains, for changes in lengths ofthe chains cause opening and closing of the tongs, and the chains arealways loaded with sufficient Weight to insure stability.

Having thus described my invention, what I claim as new therein', anddesire to secure by Letters Patent, isy 1. In combination with atraveling bridge, Wheels upon which it travels and short shafts carryingsaid wheels; a counter-shaft extending the length of the bridge andhaving reducinggear connection with each of said IOO IIO

short shafts, an intermediate short shaft having reducing-gearconnection with the counter-shaft, a sleeve supported by and turning onthe counter-shaft, having at one end reducing-gear connection with theintermediate short shaft, an electric motor and reducinggear connectionbetween the shaft of said motor and the other end of the sleeve.

2. In combination with a traveling bridge, wheels upon which it ltravelsand short shafts carrying said wheels; a counter-shaft extending thelength of the bridge and having reducing-gear connection with each ofsaid short shafts, an intermediate short shaft having reducing-gearconnection with the counter-shaft, a sleeve supported by and turning onthe counter-shaft, having at one end reducing-gear connection with theintermediate short shaft, an electric motor and reducinggear connectionbetween the shaft of said motor and the other end of the sleeve; saidcounter-shaft havinga division and a Hangecoupling therein on eachsideof the reduction-gear through which it is driven.

The combination of a lower non-rotating portion provided with centralopening, a circular tiange mounted on said portion around thecentralopening, and provided with a rack on its interior circumferenceand a guardtlange above the rack, an upper rotating portion, a pinioncarried by the upper portion and meshing with the rack, and rollers alsocarried bythe upper portion, bearing against the guard-{iange preventingthedisplacement of the upper portion.

, 4L. Inarotatabletrolley fortraveling cranes, the combination ofthelower non-rotating portion having a circular track, a verticalannular flange within said track, projecting above it, an upper rotatingportion having ,rollers running on the circular track with axes disposedradially to the trolley, and an electric motor having connectionsthrough which it rotates the upper portion of the trolley, comprising acircular rack on the face of the annular iange, a horizontal motor-shaftcarryinga screw, and a vertical shaft carrying upon its upper endaworm-wheel meshing with said screw and upon its lower end a gear-wheelmeshing with the circular rack.

5. In combination with the winding-drum of a traveling crane; anelectric motor therefor and a train of reducing-gears between'the motorand drum, embodying a shaft having a longitudinally-movable sleevesplined thereon, and carrying dierential drive-gears, and a drivenshaft, having two gears of dierent sizes fixed thereon, having theirperipheries respectively in position to move into mesh with the diierentdrivingpinions of the sleeve, and shiftable axially to bring either ofthem into mesh with its corresponding pinion.

G. In combination with the winding-drum of a traveling crane; anelectric motor therefor and a'train of reducing-gears between the motorand the drum, embodying a shaft connected with the motor-shaft, havinglongitudinally-movable differential driving gearwheels splined thereon,and a driven member having two driven gear-wheels of diierent sizes xedthereon, with their peripheries respectively in position to intermeshwith the different driving gear-wheels when the latter are shiftedaxially to bring either of them into mesh with its corresponding drivengearwheel.

`7. In an electric crane, the combination of a single electric motor, apair of hoistingdrums and identical driving connections between themotor and both drums embodying a common d rive-pinion which receivesmotion from the motor, independent drum-shafts having at one endgear-wheels with both of which the drive-pinion meshes, .passing throughand turning within the drums, and having at their other endstransmitting gearwheels, gear-wheels carried by the drums, and 'anelectromagnetic brake for both drums comprising a brake-band wheelgeared to one of the drums, a brake-band, a brake-band lever and asolenoid.

8. In an electric crane, the combination of a single electric motor, apair of hoistingdrums and identical driving connections between themotor and both drums embodying a common d rive-pinion which receivesmotion from the motor, independent drum-shafts having at one endgear-wheels with both of which the drive-pinion meshes, passing throughand turning within the drums, and having at their other endstransmitting gearwheels, gear-wheels carried by the drums, connectionsbetween each transmitting-gear and the gear on the drinn, and atongs-controlling drum also geared to and driven by the shaft of one ofthe transmitting-gears.

` 9. In an electric crane, the p combination with a hoisting drum, atongs controlling drum and a motor common to both drums, of a slip-jointhaving a limited movement introduced in the driving connections of oneof said drums.

l0. In an electric crane, the combination with a hoisting drum, a tongscontrolling drum, and a motor common to both drums, of a slip-jointhaving a limited movement introduced in the driving connections of oneof said dru ms,and a retarding-brake acting upon the drum having theslip-joint inits connections.

11. In an electric crane, the combination with a hoisting-drum, atongs-controlling drum and a motor common to both drums; of a slip-jointintroduced in the driving connections of one of said drums comprising apawl-and-ratchet and a frictional driving connection.

12. In an electric crane, the combination with a hoisting-drum, atongs-controlling drum, and a motor common to both drums, of aslip-joint introduced in the driving connections of one ot' said drumscomprising a pawl-and-ratchet and a frictional driving conyroo IIO

5 the drums.

to resist turning of said drum; the relation power having drivingconnection with said nection, and a retarding-brake acting upon the drumhaving the slip-joint in its connections.

13. In an electric crane, the combination l of a hoisting-chain drum, acontrolling-chain drum, connections for driving the drums, a brake forone of the drums, and a slip-joint having a limited movementinterposedin the driving connections for one of the drums.

I4. In an electric crane, the combination of a hoisting-chain drum, acontrolling-chain drum, connections for driving the drums, a brake forone of the drums, and a slip-joint having a limited movementinterposedin the driving` connections for one of the drums comprising a frictionaldevice bearing against one part and engaged by the other.

15. In an electric crane, the combination of a hoisting-chain drum, acontrolling-chain drum, connections for driving the drums, a brake forone of the drums, and a slip-joint interposed in the driving connectionfor one of the drums comprising a frictional strap surrounding one partand a paWl-and-ratchet connection between the friction-strap and theother part.

16. In an electric crane, the combination of a hoisting-chain drum, acontrolling-chain drum, connections for driving the drums, a brake forone of the drums, and a slip-joint interposed in the driving connectionfor one of the drums comprising a frictional strap surrounding one partand a pawl-and-ratchet connection between the friction-strap and theother part engagingin the direction of Winding but slipping in thedirection of unwinding.

17. In a crane, the combination of a main and an auxiliary drum, a'common driving power having driving connection with said drums, meanspermittinglost motion between said drums, comprising a yielding drivingconnection for one of the drums, and means between the yielding drivingconnection and the resistance being varied, in the movement of said drumin opposite directions.

18. In a crane, the combination of a main and an auxiliary drum, acommon driving drums, and a slip-joint permitting lost motionbetweensaid drums, and yielding more readily in one direction of rotation ofthe drums than in the other under means for imposing a resistance to theturning of one of 19. In a crane, the combination of a main and anauxiliary drum, a common driving power having driving connection withsaid drums, a slip-joint permitting lost motion'between said drums, andyielding more readily in one direction of rotation of the drums than inthe other, under a resistance imposed on one ofthe drums, and means forlimiting the lost motion.

20. In a crane, the combination of main and auxiliary drums, a commondriving power having driving connections with said drums, a slip-jointinterposed in the driving connection of one of the drums, permittinglost motion between the drums, yielding under abnormal resistanceoffered by the drum which it drives, and overcoming greater resistancein one direction of rotation than in the other.

2l. A crane having a hoisting-drum, a plurality of load-bearing chainsattached to said drum at separated points thereon, and inclineddownwardly toward each other, suitable carrying means supported at thelower ends of said chains, an additional hoistingdrum spaced apartfromthe hoisting-drum rst named, and load-bearing chain connectionbetween the carrying means and the second drum, inclined downwardlytoward and connected at a common point with the rstmentionedload-bearing chains, and forming therewith a pyramidal system ofhoistingchains.

22. In a traveling crane, a system of four hoisting-chains in the formof an inverted pyramid the base of which is formed by the four points ofattachment of the chains to the winding means.

23. In a traveling crane, the combination ot' a rotating trolley, a pairof hoisting-drums on the rotating trolley and a pair of hoistingchainsattached to each drum, at opposite ends thereof,and inclined inwardlyand downwardly to the load-bearing connection, such as tongs and thelike.

24. In a crane, the combination of a pair of hoisting-drums, a pair ofchains attached to opposite ends of each hoisting-drum, and inclined toform an inverted pyramid and a controllingchain drum also having a pairof chains secured to its opposite ends and inclined toward the apex ofthe pyramid.

The foregoing specification signed this 13th day of November, 1901.

JOHN H. HOLLAND.

In presence of- R. B. BRYSON,- W. F. BILLINGSLEY.

IOO

